The invention relates to an apparatus for preparing dialysis a liquid which is used for hemodialysis.
Hemodialysis is an effective treatment for renal insufficiency. Hemodialysis consists of circulating blood and dialysis liquid through a hollow fiber semi-permeable module that uses a polymer membrane made of cellulose or polysulfone, and so forth, to remove waste products and excess water from the blood. The dialyzed blood is returned to the patient. Dialysis liquid is prepared from an acetic acid based preparation (A Preparation) and bicarbonate based preparation (B Preparation). The preparation is available commercially in the form of a concentrated liquid including dextrose, sodium chloride, potassium chloride, calcium chloride, magnesium chloride, acetic acid and so forth. The B preparation available commercially in the form of powders including sodium bicarbonate and sodium chloride. As a dialysis liquid preparing apparatus, for automatically preparing a dialysis liquid, Japanese Unexamined Patent Publications (Kokai) No. 9-618 and No. 4-84967 describe an apparatus which injects water into a bottle in which a powder is sealed, allows the entire amount to flow into a tank, and stirs and mixes the solution in a tank equipped with a stirrer, as well as an apparatus that mixes using a circulating pump.
Further, Japanese Unexamined Patent Publication (Kokai) No. 5-168678 describes an apparatus which holds a quantitative powder container in the inverted state, allows the powder to drop naturally into a tank, and then stirs and mixes the powder in the tank.
Normally, 0.12 m3 of dialysis liquid is required for a four-hour dialysis. Therefore, a relatively large tank of, or larger than, 0.12 m3 is required for such a prior art dialysis liquid preparing apparatus which results in an increase in the volume of the apparatus and its complex piping system.
On the other hand, contamination of the dialysis liquid preparation apparatus and the dialysis liquid supply lines leads to bacterial growth in the lines which causes fever in patients due to endotoxins. It is therefore necessary to clean and sterilize the dialysis liquid preparing apparatus and the dialysis liquid supply lines before and after use as well as the dialyzer itself. Thus, an arrangement facilitating the cleaning and sterilization of the apparatus is important for a dialysis liquid preparing apparatus and the stirrer and the complex piping system results in a relatively long time for cleaning and sterilizing the apparatus.
Further, Japanese Patent No. 2753242 describes a dialysis liquid preparing apparatus which supplies water to a sealed cartridge of a solid preparation for preparing dialysis liquid to remove the dissolved concentrated liquid. For the dialysis liquid preparing apparatus, special cartridges with powder enclosed must be produced. Further, according to the method disclosed in the publication, it is difficult to keep the concentration of the prepared concentrated dialysis liquid constant. In order to solve this problem, the concentrated dialysis liquid must be removed as a saturated solution so that an amount of powder preparation more than the amount necessary for one dialysis must be filled in the cartridge.
The invention is directed to solve the problems of the prior art, and to provide a dialysis liquid preparing apparatus which realizes a simple constitution by eliminating the tank, which occupies a substantial portion of the apparatus, to reduce the volume of the apparatus. The apparatus is also improved sanitarily by completely using one prescribed amount of the preparation.
Further, the object of the inventions is to provide an economical dialysis liquid preparing apparatus which allows one prescribed amount of the powder preparation for preparing dialysis liquid to be dissolved in a short time to prepare a concentrated dialysis liquid of a constant concentration.
According to the invention, an apparatus for preparing dialysis liquid which comprises a container holder for holding a container in the inverted state, the container having a tubular body portion which defines an internal volume for accommodating powder preparation for preparing dialysis liquid, a bottom wall defined at an end of the tubular body portion, and a sealing member for closing an outlet opening defined at the end of the tubular body portion opposite to the bottom wall, a cutter, movable toward and away from the sealing member, for cutting the sealing member, a concentrated liquid tank provided under the container holding means, a mesh member, horizontally disposed above the tank, for receiving the powder preparation which has fallen from the container and a nozzle for applying water to the powder preparation for preparing dialysis liquid which has fallen on the mesh member from the container after the sealing member is cut by the cutter. The water is applied to the powder preparation for preparing dialysis liquid dropped on the mesh member to produce a concentrated liquid for the dialysis liquid, which is received in the concentrated liquid tank, and the concentrated liquid is diluted with diluting water as it is supplied to the dialyzer.
In the dialysis liquid preparing apparatus of the invention, a large tank can be eliminated by preparing a dialysis liquid of a predetermined concentration by diluting a concentrated dialysis liquid of a predetermined concentration with water. The dialysis liquid preparing apparatus of the present invention do not require a large tank. Therefore, the amount of water and electricity necessary for cleaning and sterilization of the apparatus are considerably decreased compared with, for example, the batch type dialyzer having a dialysis liquid preparing apparatus and a large tank disclosed in Japanese Unexamined Patent Publication (Kokai) No. 9-618.
Further, the apparatus of the invention can dissolve one unit of prescribed amount of powder preparation within a short time to prepare the concentrated liquid and uses a new bottle for each treatment. Therefore, it is economically and sanitarily improved. Further, the apparatus of the invention allows cleaning and sterilization to be executed easily by circulating hot water through the apparatus. The simple configuration of the dissolving apparatus facilitates the cleaning, which improves the apparatus sanitarily.